Steam is the number one reason why PC gaming has suddenly flourished in the last two years or so.
I think Call of Duty, Mass Effect 2, Dead Space 2, and Star Craft 2 had more of a hand in that than Steam.
Not trying to defecate on what you said but Steam is just a platform to provide in-home window shopping for games, it's the content that counts no matter which way you put it.
What about the website Good Old Games? (www.gog.com) They seem to have a really good community. It would help raise awareness a lot to an "older" and more receptive gaming community. I'm pretty sure Good Old games have agreements with Activison as well because they have published a lot of the older games from Troika and the like.
What's certain is that something should be done to re-ignite the SC community.